Means for preventing current leakage in electric cables.



S. D. SPRONG 6: W. E. McCOY. MEANS roR PHEVENTING cunnfut LEAKAGE IN ELECTRIC CABLES.

APPLICATION FILED DEC. l2 ISIS.

.Patented Aug. 2l, 1917.

73E/n1 no fr UNITED STATES PATENT OFFICE.

BEVEBN D. BPBONG AND WALTER E. MUCUY, UF NEW YORK, N. Y.

MEANS FOR PBEVENTING CURRENT LEAXAGE IN ELECTRIC CABLES.

Speolcatlon of Letters Patent.

Patented Aug. 21, 1917.

Application led December 12. 1918. Borla! No. 186,401.

To all whom t may concern:

Be it known that we, Snvnim D. SrnoNo and WALTER E. MoCoi', citizens of the United States, residin at New York, in the county of New Yor and lState of New York, have invented a certain new and useful Improvement in Means for Preventin Current Leakage in' Electric Cables, o which the following is a specification.

The invention is a pot-head for the end of a high tension cable, so constructed as to prevent current leaka e from the conductors of said cable to t e metal of the othead, and so elsewhere-as to other ca les or to ground. The invention consists in the construction more particularly pointed out in the claims.

In the accompanying drawingsv Figure 1 is a longitudinal section of our ot-head. Fig. 2 is a cross section on the ine zo, a: of F ig. 1. Fig. 3 is an enlarged lo itudiiial section of the cover joint imilar numbers of reference indicate like arts.

Our potliead is herein sho-wn applied to a cable`co`ns`tructed as set forth in U. S. Letters Patent No. 1,165,141, ranted to us December. 21st, 1915. Said ca le comprises three longitudinally bent and mutually interlocking plates 1, 2, 3, of insulating niaterial, which unitedly form a tube 4 dlvided interiorly into 4three compartments Said plates are incased in a complete tube or cylinder 5 of insulatin material, and said tube in turn is inserted in the open end of a metal pot 6. The line cable has three metallic conductors-two, a, a, shown in Fig. 1- rovided,with the usual individual insuation and inclosed in a single insulating sheath 7, which sheath in turn is in; closed in the metal sheath 8. Said line cable enters the pot 6 through an opening in the bottom thereof, and is here shown secured to said pot b a wi ed joint 9.

The branch con uctors to be connected to the three conductors of the line cable are shown at 10, 11, 12. Each has two insulating envelops 13, 14. Said branch conductors 10, 11,412 respectively pass through three sleeves (two shown at 15, 16 in Fi 1) formed integrally on the inner side o the lian ed cover 17 of porcelain or other ma teria Said sleeves extend into the compartments formed by plates 1, 2, 3. The metallic conductors of the line cable are connected to the metallic conductors 10, 11,

12 of the branch lines by couplings 18 within said compartments.

It is to be particularly noted that the outer end of the tube or cylinder ligand the outer ends of the plates 1, 2, 3 extend beyond the outer end of pot 6, so that the inner face of said cover bea-rs against the ends of said tube and plates, and its flange 19 extends over the end portion of the pot 6.

In this way, we form a closed annular' air s )ace 21 between the extremity of pot y6 and t e inner surface of cover 17.

The entire space within the ot is to be filled with any suitable insu ating compound, which may be .introduced in a plastic state and allowed to harden. In Fig. 1 only the outer portion of the pot, shown at 20, is so filled the remainder bein represented as unfilled, more clearly to ow the construction. A spreading block 22 of solid insulating material, supported in any suit able way, may be placed between theconductors of the line cable. The pot ma be supported on a fixed lug or bracket, indicated at 23.

Particular attention is now called to Fig. 3. The object of the construction here is' to prevent current leak e at the joint This We accomplish by ma in the ath of the leakage current longer an to o er more resistance than the dielectric path. Thus in Fig. 3, the dielectric path from the metal conductor 11 to the metal wall of pot 6 is represented by the straight arrow A, On the other hand, the leakage path of current fronr the said conductor 11 to pot 6 is represented by the bent arrow B. In other words, any leakage current from conductor 11= after traversing the insulation on said conductor and the filling around said insulation, must travel along the joint between cover sleeve 16 and the Wall of the compari'. ment formed by the bent plate 3, then around the end of said )late and of the inclosing cylinder 5, and t en along the outer surface of said cylinder before it can reach the end of pot 6.

We claim:

l. A pot-head for hi h tension electric cables, oomprisi two tu ular casin of insulating materia one within the ot er and separated by an air space, a plate of insulating material closing one side of said space, and a tubular casin of metal having one end partly filling an closing the other side of said space.

2. A pot-head for high tension electric cables, comprising a metal pot having an openin in its closed end, a tubular casing o insu ating material within said pot an extending beyond the outer end thereof, a aligled cover of insulating material for said pot aving an opening, and a sleeve on the inner side of said cover registering with said opening and entering said casing; whereby an annular air space is formed between said cover and-thexend-of said pot and surrounding the protruding end portion of said casinlgf 3. A potead for high tension metal sheathed electric cables, comprising a metal ot havin an opening in its bottom receiving said ca le and at said opening being electricall connected to the cable sheath, a flange cover of insulating material for the open end of said pot, a sleeve of insulating material on the inner side of said cover, a tubular casing of insulating material within said pot and receiving said sleeve, a conduc tor passing through said sleeve, entering said tubular casing and being electrically con' nected therein, and a filling of insulating material within said pot and said casing; the said casing extending beyond the outer end of said pot, and the said cover flange extending over the end portion of said pot, whereby an annular air space is formed between said-cover and the end of s'aid pot, and surroundingthe protruding end portion of said casing.

4. A; `pothead for high tension metal sheathed electric cables, comprising a metal ot having an opening in its bottom receivlng said cable and at said opening being electrically connected to the cable sheath, a

anged cover of insulating material for the open end of said pot, sleeves of insulating material on the inner side of said cover, a tubular casing of insulating, material within said pot, partitions 'of insulating material within sai. casing dividing the same into longitudinal compartments respectively receiving said sleeves, the conductors of said cable respectively entering said compartments, branch conductors passing through said cover sleeves and entering said compartments and electrically connected therein to the said cable conductors, and a. filling of insulatin material within said pot and said casing; t e said casing extending beyond the outer end of said pot, and the said cover fiange extending over the end portionof` said pot, whereby an annular air space is formed etween said cover and the end of said pot, and surrounding the protruding end portion of said casing.

5. A pot-.head for high tension electric c-ables, comprising a metal pot having an openin in its bottom, a tubular casing of insulating material within said pot, a cover of insulating material for said pot having an opening, a sleeve on the inner side of said cover registering with said opening, and two line conductors respectivel entering said pot and said casi throng said bottom pot opening and sai cover opening and united together within said casing,

In testimony whereof we have ailixed our signatures in presence o two witnesses.

SEVERN D. SPRONG. WALTER E. MoCOY. Witnesses:

GERTRUDE T. PORTER, MAY T. MCGARRY.

duplex et. this patent may be obtained for ave cents each, by addressing the Commissioner of Patents, Washington, D. G. 

